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[skadamo]

Hey Guity, this stuff is a little over my head but I'm learning a lot. Came across this post and thought it might help with your approach to balancing your pack...

http://jackrickard.blogspot.com/2009/11/get-rid-of-those-shunt-balancing.html

or it could be just an interesting side note.

[guity]

Thanks Skadamo, I skimmed over it some and will read it more carefully tomorrow.  I am already a bit of a disciple of this guy.  I really want to balance these cells from the bottom.  But I can't really get to the bottom with the equipment at my disposal unless I can actually run the bike.  But now that I have me Cheap-O battery monitoring system in place, I will be able to monitor the voltages of the cells and drain or charge individual cells by just taking the gas tank off, as opposed to taking the heavy battery trays off the bike.

Tonight I ran the Alltrax controller settings program and changed the low voltage cutoff to 60 (the largest value you can choose).  Now I have 24 batteries running and if they all had the minimum 2.5 volts that would add up to the 60 volts cutoff stipulated in the program.  But if one or more of the cells is running a tenth of a volt lower or 2 or 3, then by the time all the other cells hit an average of 2.5 volts and trigger the cutoff, the cell(s) that were a tenth of a volt (or 2 or 3) lower would now be at 24 volts or 2.3 volts or 2.2 volts, and therefore be damaged.

At any rate, I want to run the bike until the cells avergae about 3.0 volts per cell, and then stop the bike and balance the cells at that level, to try to follow in line with what Rickard is saying.


Anyway, I guess tomorrow I'll find out if I can still remember what parts of the bike go where and if I can put them all back together in one piece again....

[guity]

These are the Alltrax controller settings I found on my bike last night after hooking my computer into the controller.  As stated yesterday I changed the low voltage cutoff to be 60 -- and would have gone higher if I could have.  Today I also changed the maximum output setting to be 100% rather than the 84% I found it at.  Tonight I opened the bike up full throttle on a steep part of the hill I live on.  It still seemed a bit sluggish, but was operating from a base of around 79-80 volts, so even with open throttle up the steep hill for 2 or 3 minutes, it never managed to sag to less than 65 volts  -- whereas with the 22 batteries I was sagging below 55 volts coming up a portion of the hill that is not as steep.

When I come back down the hill I wind up doing some fairly heavy braking so it is common for the bike to stink a bit when I get it back in the garage.  Tonight I actually saw smoke rising in the air in front of the headlight as I pushed the bike into the garage, as well as the stink.  This is pretty worrisome seeing as how I just dis-assembled and re-assembled the bike and there are plenty enough gaps in my knowledge to have done something stupid to cause the bike to burn itself out somehow.  But until tomorrow and further testing I will be optimistic and point out that the smoke shown by the headlight was coming up from a place where only the front wheel had been -- the motor and batteries never got that far into the garage...

[guity]

The good news is that the smoke and stink were almost surely from the brakes.  A longer harder ride today produced no smoke or stink.

The bad news is that I am still reaching low voltage cutoff too soon.  My latest thought is that while only 2 of the batteries were killed, a lot more of them were damaged in a lesser way that causes them to sag in voltage under heavy loads (like going up hill).  Over the last couple of weeks, trying to balance them, and getting used to some of their individual quirks, I can see a pattern in the way the 2 new batteries and the 1 spare (un-abused) battery perform compared to the others: when the batteries are all being charged together, the 3 new ones are much slower to reach the higher voltage levels.  At the same time, when those batteries are drained, they are much slower to leave their operating voltage levels.

I got hit with LVC about 17 miles into a charge cycle, the last half mile up to my house.  It was kind of ironic that after I stopped, the batteries quickly floated back up to a total of 79.8 volts, just a few tenths of a volt less than where they started.  These things could still go a good 60 miles on flat ground, I think, but their hill-climbing glory days appear to have ended...

[guity]

There it is, Picasso, the tool that makes it livable to try to balance the batteries on my GPR-S.  THANKS!

[guity]

Going back over the cycle analysat stats, I noticed that before I abused the batteries, my typical voltage sag on a commute day (18 miles) was around 10volts.  However, since the abuse, the voltage sag on that commute has been in the 13 and 19 (last night it was 19) volt range.  Does that mean that one or more batteries in my pack is/are still bad, though they aren't completely dead yet?

[guity]

What does it mean if one of your lifepo batteries is at 3.22 volts at the end of a cycle while the next lowest battery after that is at 3.30?  What if the battery in question is bloated with gas and is stinky as hell from leaking battery paste all over the place?

I mean, I know that can't be a good thing, but can it make the other 23 batteries seem like they are actually less than 23 (like they are 21 batteries, let's say)?  Can that one bad seed battery reduce your top speed from 59 mph to 53 mph?  Can it make your voltage sag double when going up long steep hills?  Or will it take more than that one culprit to cause so much trouble?

Right now I've already ordered a replacement battery for this one -- I certainly hope I'm not jumping the gun, replacing a battery that doesn't really need it.  And to a lesser extent, I hope that I am not missing some other battery or other batteries that need replacing just as much....

[guity]

While I wait for a replacement 60 AH Thundersky, I want to prove the fat stinky leaky battery is bad by discharging it down to 2.5 volts by itself (so it can't suck any juice from its neighbor batteries) using my 30 watt light bulb attached to it with wires and alligator clips.  The I will attach my 2 amp Tenergy charger to it.  Whatever number of hours it takes for the Tenergy light to turn green, indicating that the battery is fully charged, multiplied by 2 (it is a 2-amp charger), will be the number of amp hours in the battery.  If the battery isn't holding somewhere close to 60 amp hours any more, then I believe it sucks and should be exiled from the pack...

[EVmc]

hope ypu took some time off for christmas and had a nice one
this is kinda long
i put > for my reply, lots to keep track of for my peabrain

I’d put Alltrax  max output settings   back to 85% take it easy until pack is balanced.
> thank you I won’t worry so much
>Alltrax low voltage cutoff to 60 volt - mismatched for a 24 cell pack needs to be 64.8 to 67.2 >volt, 2.7, 2.8 per >cell
>Never want any cell to go below 2.7 volt no reason at all to hit 2.5 per cell except a bad >reason.


Tonight I opened the bike up full throttle on a steep part of the hill I live on.  It still seemed a bit sluggish, but was operating
 >from a base of around 79-80 volts, /24 =3.31 v good
 so even with open throttle up the steep hill for 2 or 3 minutes, it never managed to
> sag to less than 65 volts /24 = 2.708 cell volt average good –
> whereas with the 22 batteries I was sagging below 55 volts/22=2.5 cell volt average-
>danger warning Will Robinson
 coming up a portion of the hill that is not as steep.


When I come back down the hill I wind up doing some fairly heavy braking so it is common for the bike to stink a bit when I get it back in the garage.  Tonight I actually saw smoke rising in the air in front of the headlight as I pushed the bike into the garage, as well as the stink.  This is pretty worrisome seeing as how I just dis-assembled and re-assembled the bike and there are plenty enough gaps in my knowledge to have done something stupid to cause the bike to burn itself out somehow.  But until tomorrow and further testing I will be optimistic and point out that the smoke shown by the headlight was coming up from a place where only the front wheel had been -- the motor and batteries never got that far into the garage...

>Does the stink smell like epoxy, when you mix it?
>That’s what lions smell like when vent
>Smoke from headlight , on high beam is there some silver reflective material below the bulb >on the bezel?
>It needs to be there or will melt the plastic
>The brakes should never smoke or smell, something wrong.

The good news is that the smoke and stink were almost surely from the brakes.  A longer harder ride today produced no smoke or stink.

The bad news is that I am still reaching low voltage cutoff too soon.  My latest thought is that while only 2 of the batteries were killed, a lot more of them were damaged in a lesser way that causes them to sag in voltage under heavy loads (like going up hill).  Over the last couple of weeks, trying to balance them, and getting used to some of their individual quirks, I can see a pattern in the way the 2 new batteries and the 1 spare (un-abused) battery perform compared to the others: when the batteries are all being charged together, the 3 new ones are much slower to reach the higher voltage levels.  At the same time, when those batteries are drained, they are much slower to leave their operating voltage levels.

>cycle the new batteries by themselves several times until they start acting like the rest of >the pack
> and cells charge discharge too fast or slow
>then add to pack.
>Yes you are seeing the rhythm in the charge/discharge takes a few cycles to get rhythm >you’re learning!
>The hard way but are learning.
>You can put on a bench and wire in Parrell, copper plumber tape works well
> run it up run it down , can charge/discharge individual cells as needed till all work the same.
> I will try that toaster idea I like it

I got hit with LVC about 17 miles into a charge cycle, the last half mile up to my house.  It was kind of ironic that after I stopped, the batteries quickly floated back up to a total of 79.8 volts, just a few tenths of a volt less than where they started.  These things could still go a good 60 miles on flat ground, I think, but their hill-climbing glory days appear to have ended...



Going back over the cycle analysat stats, I noticed that before I abused the batteries, my typical voltage sag on a commute day (18 miles) was around 10volts.  However, since the abuse, the voltage sag on that commute has been in the 13 and 19 (last night it was 19) volt range.  Does that mean that one or more batteries in my pack is/are still bad, though they aren't completely dead yet?

> could be bad or off balance

What does it mean if one of your lifepo batteries is at 3.22 volts at the end of a cycle while the next lowest battery after that is at 3.30? 

>Checked right after discharge cycle? Or after an hour rest?
>After rest Thundersky manual says .1v difference balanced
>1v lower than the others is abnormal

What if the battery in question is bloated with gas and is stinky as hell from leaking battery paste all over the place?
>BAD smells like epoxy? I have seen them vent and smell but haven’t seen paste coming out.
>I’ve seen a pack that was hot for over a day, smelled , but no paste coming out
>swelled?
> are the cells next to swelled ones, pushed in, like curved matching the swell out one next to >it?
> I’ve seen that happen, check those. need discharged to 2.8v clamped to push back in >shape, charge/discharge but >only go  3.8v, 2.8v several times.


I mean, I know that can't be a good thing, but can it make the other 23 batteries seem like they are actually less than 23 (like they are 21 batteries, let's say)?
> yes say it drops fast to1.2v or 0v or reverses -2volt
>23cell at 3v=69v + 1 cell at 1v=70volt

 Can that one bad seed battery reduce your top speed from 59 mph to 53 mph?  Can it make your voltage sag double when going up long steep hills?  Or will it take more than that one culprit to cause somuch trouble?

> yes will drag down the other cells as they have to work harder to keep up with demand

Right now I've alreayd ordered a replacement battery for this one -- I certainly hope I'm not jumping the gun, replacing a battery that doesn't reallyneed it.  And to a lesser extent, I hope that I am not missing some other battery or other batteries that need replacing just as much....


While I wait for a replacement 60 AH Thundersky, I want to prove the fat stinky leaky battery is bad by discharging it down to 2.5 volts by itself (so it can't suck any juice from its neighbor batteries)

>Just go to 2.8v charge to 3.8 cycle several times watch if getting better you mentioned you >are getting the rhythm of cycling you’ll  be able to tell if improving. Work it until it holds what >the other cells hold at rest after charging
>Rest after charge reading is at least 2 hours after charge.
> but is stinky leaking not much chance good

>Hey I like your cycle analyst stats
>I added my charge chart, what I use cycling a pack to write down numbers. Have some cute >graphs
> just delete cell numbers I have in. I print out use in shop
> I may have problem posting if so see if site has email to you I haven’t used this site that >much
> I can’t stand looking at the hacked up battery box, I’ll make you a new one if you want, if >you pay shipping $13 or less I think. I have dimensions, on the first ones I punched square >holes for cell removal, will put those in. No charge for the box.
> I am sure EMS would want you to have a new box.

[EVmc]

charge chart
charge chart blank

[guity]

Thanks very much for all the time and attention to my plight EVmc!  I kind of ran into a brick wall with the fat stinky leaky battery.  I put a single cell charger on it and got it up to 3.5 volts.  That wasn't quite right because the Tenergy charger is supposed ot charge a battery up to like 3.65 volts and then signal the end with a green light.  At any rate, the 3.5 was higher than the other batteries, 22 of which were at 3.33 volts, and one of which was at 3.32 volts.  

So I drained the stinky battery with a 30-watt light bulb, down to about 3.4 volts, because I kind of figured if it was weaker than the other batteries, it might help if I kept it charged slightly higher.  Then I plugged in the general Electric Motorsport 90-volt charger on all the batteries.  When I came back about an hour later, the rest of the batteries had only increased their voltage marginally, (maybe up to 3.36), but the stinky one was at some scary number like 5.6 volts!  As soon as I unplugged the EM charger the voltage on the stinky battery started dropping fairly rapidly, and to make it drop faster I attached the 30-watt bulb again.  Within a few minutes I had the stinky battery back down to 3.4 volts.  So I plugged in the general EM charger again.

This time I stayed to watch the stinky battery, and realized that it was climbing right back up at an alarming rate.  I let it get up to something like 4.23 and then stopped the charger and drained it back down.  But this time I drained it down below the others, like 3.2.  Then the general EM charger again.  And again the voltage on the stinky battery climbed so fast that within a few minutes it was hitting 4.2 again, much faster than the other the other batteries were able to to make any significant increase in voltage.

[guity]

I don't don't how many times I would have had to drain that stinky battery and then charge all of them together to get them up at the 3.65 level together, but I finally just gave up.  My latest conclusion is that the stinky battery is damaged, but not damaged in the sense of being unable to hold a charge.  I basically think that the stinky battery's charge/discharge curve has been altered by the damage.  So at some voltage level like 3.2, let's say, it's voltage level is shooting way up fast while the other batteries are still slowly soaking up amp hours all the way up through 3.5 volts.

My theory is that the stinky battery's discharge curve is equally screwed up, so that once it gets below 3.2 volts, let's say, it drops like a rock while the rest of the batteries are still happily churning out amp hours.  When I open up the throttle all the way or drive the GPR-S up the hill, the stinky battery quickly reaches some kind of state where it is actually sucking in juice from the rest of the batteries.  So the same hill that caused me to sag about 9 or 10 volts when I had a healthy 23 batteries runing at the same time, now causes me to sag 13 to 24 volts with 24 batteries on the same hill.

Even the 2 brand-new batteries that I installed seem much more in tune with the charge/discharge rates of the other batteries than this stinky battery.  Ditto for the 24th battery that was always in the bike but only recently hooked up.  I really hope I am right because if I replace the stinky battery and still suffer from this low top speed and excessive voltage sag then I won't have the slightest idea of where to look next...

[guity]

EVmc, thanks very much for the offer on the new battery case(s).  The truth is, I am afraid that the batteries might not fit in normal cases any more.  I am actually glad the 6-pack case is still hacked up, because otherwise I don't know how I would replace the fat stinky leaky battery.  I am not really aware of how fat most of the other batteries have gotten, but this fat happens to be the next-door neighbor of one of the batteries I replaced before.  When I finally got that dead battery out of the case, I realized that half the reason it had been so difficult was because of it's fat neighbor.

EVmc, I really think those cases should not be designed like that.  The metal sides should be held together by straps that can be loosened when necessary, so you don't have situations where a case has to be destroyed to get a battery out.  Also, the metal of the battery cases is really so thin I'm not sure how much good it does at containing the batteries.  My cases seemed like they just got pushed around by the batteries, so they just swelled and warped wherever the batteries happened to bulge.  This was before I hacked into them, and their warped-ness made it hard to get them out of the bike.

A couple times I took voltage connecting straps off batteries for one reason or another, and was unable to get the straps back on because the bulging batteries pushed eah other out of the range of the battery strap holes.  The only way to get the bolt holes to line up again was to take motorcycle ratchet tie down straps and wrap them around the pack and ratchet it tight enough to move the swollen batteries close together again.  I wish that the batteries had been tied together with similarly designed straps to begin with.

[guity]

Thanks for the charts EVmc.  I took my latest stats and slightly re-did your formula that divides the minimum battery voltage by the number of batteries.  The reason being that most of the time I was using 23 batteries, then in early December I was using 22 batteries, and now since later on in December, the bike is using 24 batteries.  So I made changes to reflect the number of batteries in the bike at any given time.  Also, I wanted to point out that the one crazy looking minimum voltage of 40 was some kind of anomaly, I believe.  

I saw that 40 volt level show up on the cycle analyst as I was driving down the hill using little or no amps.  Maybe some connection got of whack for a few seconds, or batteries freaked out for some reason, or the cycle analyst went temporarily insane, but the voltage quickly came back to normal and never came close to going that low when traveling back up the hill.  And the low voltage cutoff that day had been set to 60 volts.

[guity]

EVmc, as you pointed out, I am slowly, painfully learning.  I am like a child.  There is this inherent drama involved where it is difficult to tell which will happen first -- either I learn just enough fast enough to get the bike running at the level I want (and how to maintain it that way), or I electrocute myself and/or completely destroy the bike...